In general, CT (Computed Tomography) capturing systems, panoramic radiography equipment, cephalo imaging apparatuses, and so on are widely known as dental examination apparatuses used for diagnosing defects of teeth. Such imaging apparatuses are widely used as the basic examination apparatuses for diagnosing defects of teeth because they can rapidly make images of teeth conditions. However, because the imaging apparatuses all use X-rays, they can obtain excellent anatomical images about conditions of bones and horny tissues, such as teeth or pubic bones, but cannot obtain sufficient anatomical images about soft tissues, such as gums, and dental nerve tissues.
As an examination apparatus for obtaining higher image resolution and contrast about the soft tissues or the dental nerve tissues, an MRI (Magnetic Resonance Imaging) system using magnetic field is known. However, such an MRI system carries out examination while horizontally moving over a patient, who lies on a cradle, in a state where a magnetic field is shielded by a shielding device during the examination, and hence, the examination procedures are complicated and the patient may feel a fear of the examination in a closed space. Particularly, patients, who have claustrophobia, may refuse examination itself. Moreover, because conventional MRI system is designed to move over the whole body of the patient and requires the shielding device for shielding harmfulness by the magnetic field, the system is big in size and is very expensive. Furthermore, because the conventional MRI system uses a superconductive magnet and is designed to have a large imaging space so that the MRI system moves over the whole body of the patient, it is large in output quantity for operating the superconductive magnet, a gradient coil, an RF coil and so on, and hence, its maintenance fees and management fees are increased. Accordingly, the conventional MRI system is used only for emergencies or critical diseases, such as brain tumor and is rarely used for dental diagnosis, such as examinations of soft tissues, such as gums, and dental nerve tissues. For instance, MR images of soft tissues, such as gums, and dental nerve tissues for dental diagnosis are incidentally obtained and used when brain tumor or one of other critical diseases is examined.
Therefore, in order to conduct dental diagnosis to judge defects in the soft tissues, such as gums, and dental nerve tissues, development of a dental MRI system, which can easily and simply obtain MR images at lower costs, is demanded.